21022112221 has 16 divisors (see below), whose sum is σ = 24147417600. Its totient is φ = 18099774000.

The previous prime is 21022112213. The next prime is 21022112227. The reversal of 21022112221 is 12221122012.

It is a happy number.

It is not a de Polignac number, because 21022112221 - 2³ = 21022112213 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21022112195 and 21022112204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21022112227) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 791800 + ... + 817918.

It is an arithmetic number, because the mean of its divisors is an integer number (1509213600).

Almost surely, 2^21022112221 is an apocalyptic number.

It is an amenable number.

21022112221 is a deficient number, since it is larger than the sum of its proper divisors (3125305379).

21022112221 is a wasteful number, since it uses less digits than its factorization.

21022112221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30000.

The product of its (nonzero) digits is 64, while the sum is 16.

Adding to 21022112221 its reverse (12221122012), we get a palindrome (33243234233).

The spelling of 21022112221 in words is "twenty-one billion, twenty-two million, one hundred twelve thousand, two hundred twenty-one".